Generally, touch-screen display devices detect input from a user based on the presence and location of a touch on, within, or within the vicinity of the surface of the display area. Some touch-screen display devices require physical contact with the surface of the display area, for example with a finger, stylus, or other input mechanism, in order to interact with the touch-screen display device. Other touch-screen display devices receive input by detecting the presence of a finger, a stylus, or some other input mechanism hovering around, or otherwise in the vicinity of, a particular location on the surface of the display area.
Multi-touch display devices are more sophisticated than traditional touch-screen display devices, as they detect the presence and location of multiple touches on, within, or within the vicinity of the surface of the display area at the same time. Like traditional touch-screen display devices, some multi-touch display devices require physical contact with the surface of the display area with one or more fingers, styluses, and/or other mechanisms in order to interact with the multi-touch display device, while other multi-touch display devices receive input by detecting the presence of one or more fingers, styluses, and/or other input mechanisms hovering around, or otherwise in the vicinity of, the surface of the display area.
Multi-touch display devices belong to a more general class of multi-point input computing systems. Multi-point input computing systems receive, recognize, and act upon multiple inputs at the same time.